I am using a OS 140RX. and have ran this engine in intermediate, advanced and now Masters. A very trouble free set up.

A couple things to remember a 140RX is a rear exhaust and will need a header and a pipe.

A 160FX can use a stock muffler big and ugly or a pitts style muffler. The engine will really wake up with a header and pipe. Along with a Perry pump.

A 170DZ will aso need a header and a pipe.
PM if you want to talk. And curious where do you fly at.

Dennis